One of the most important issues that NEEDS to be considered is that good health seen in a baby or young child is completely irrelevant to this decision. It means NOTHING. Really- I don't care how uncomfortable that statement makes anyone as they hold their toddler and dream about another ...and I am not sitting here to tell you that your decision will be wrong- it's an extremely personal choice. But my point is, you MUST go into it with eyes wide open and fully informed.
Can you afford another baby? Can you afford another baby with serious health needs - the kind of needs you see on the most intimidating threads here, the kind you are almost afraid to read? No, those things may never happen to you, but you increase the odds if you end up having two children with this disease. Have you considered the financial aspects at least as seriously as you would purchasing a house? This is a much greater commitment than that.
Yes, we all hope and pray that vertex drugs and the others we hope will follow will change the face of cf as we know it. But until it's a done deal, until we see them having sustained, long term benefits, we cannot put all our eggs in that basket, so to speak. We can be optimistic (2016 is where my hopes lie!) but we just do not know yet.
Our personal experience, since others have shared theirs~
My daughter was a healthy chubby baby and toddler, nothing about her would have EVER screamed 'CF' and she wasn't getting a bit of care (not yet dx'ed.) Her growth slowed and essentially stopped as the years passed. She started getting sicker more often- by 6 it was to the point of panic on my part, she was NOT the same kid we had the first 3 years of her life. At 7.5 she was finally dx'ed. At this point, at nearly 11, she's lost 25% of her lung function the last couple years, been admitted 4 times in less than 2yrs, had IV's twice, has a gtube and takes 19 meds and dr-prescribed supplements. She is NOT unique in any of this, on the sliding scale of CF, she's not 'severe' by any means. Her good health as a little one was not unique either- it's actually rather common and not at all a predictor for the years to come.
My oldest has now been dx'ed with CRMS and CF has not been ruled out for him. He was 11 when Emily was dx'ed. Talk about a delayed onset of symptoms! His lung function is considerably worse than his sister's. Puberty seems to be what really set him off. It is very difficult and frustrating at this point to cope with. That is all I will say about that, it's just too fresh and new and difficult for the whole family.